The royal couple were given a guided tour of the gardens on the last full day of their South African visit before moving on to Tanzania.

Prince Charles and the Duchess of Cornwall were mobbed by excited tourists as they strolled through the bucolic gardens against the breathtaking backdrop of Table Mountain's jagged outline.

They were shown three different model gardens which were among the 31 gold and four silver winners from the past 36 years of the Chelsea Flower Show.

The most recent winning garden was awash with tiny versions of the Protea, the red and pink cup-shaped national flower, and another showed the ravaging effects of climate change, with only the hardiest and least thirsty plants thriving.

"It's a major exercise in planning, isn't it? To put all of this in," the Prince remarked. "I always think the people who make these models are brilliant."

The Prince asked if there would be a Kirstenbosch garden at Chelsea again next year, and was told it depended on funding and sponsorship.

"Well the state governor is right here," the Prince joked, turning to Helen Zille, the Premier of the Western Cape and leader of the official opposition party in South Africa, the Democratic Alliance.

The Prince questioned Edmund Gouws, who provides the seeds for the Chelsea displays, at length about how long the plants take to come to maturity. Mr Gouws said afterwards, grinning in relief as the Prince and his entourage moved off: "My business is plants, not people, so I'm not too good at all this."

The royal party was frequently approached by camera-wielding tourists. "I'm not too good at Korean," the bemused heir to the throne told one woman from the Far East who tucked her arm around his to pose for a picture.

Another woman, Dawn Dulhunty, from Brisbane, was visiting Cape Town with her husband Paul to celebrate her 60th birthday. They were busy inspecting the succulents when the Royal procession came upon them.

"The Prince said to me: 'My mother was in Australia recently'," Mrs Dulhunty said. "He asked how the floods were, whether we were there.

"As it happened, he weren't at the time so we were lucky. This was a lovely birthday present."

The Royal couple were shown around the medicinal garden by Phakamani Xaba, one of Kirstenbosch's horticulturalists.

Among the plants the Prince was shown was the helichrysum, a culturally-prized plant which people burn as incense while praying.

Another thick-leaved plant which intrigued the Prince cures earache, and the small crimson Num Num fruit grows on an attractive hedge and can be eaten to cure stomach ailments.

"He certainly knows his plants," Mr Xaba said. "He said his main drive is to convince the pharmaceuticals to invest more in conservation."

In the afternoon, the Duchess heading for Masiphumelele Township outside Cape Town, where she met children from a local creche and sat in on a reading lesson.

Lizalise Mpengesi, aged four, gazed at the Duchess in amazement as she sat down beside him and told him: "My name is Camilla. Can you say 'Hello Camilla'?" The small child repeated her words earnestly, prompting his friends to clap in delight.

Meanwhile the Prince made his way to the Cape Dutch Mount Nelson Hotel for an event to promote local wool production.

There he admired the short woollen cocktail dresses worn by two of Africa's best known models, South African Donnet Dumas, 25, and Zambian Lukundo Nalungwe, 25, who was the Face of Africa in 2010.

The dresses were designed by Karen Ter Morshuizen for her Lunar label.

Charles made all three of them laugh by explaining he didn't really do high fashion. "I'm a classic, timeless man and my fashion sense only changes every 25 years," he said.